The purpose of this work is to explore in depth the nature of the sweet taste response in mammals. This response will be studied by recording the electrophysiological responses taken from the single neurons and whole nerve of the Mongolian gerbil's chorda tympani nerve. The first experiments will involve investigation of the gerbil's whole nerve response to a variety of sugar and non- sugar sweeteners to determine specificity of the response. The purpose of the second group of experiments will be to determine the number of receptor sites which are responsible for the sweetener taste responses. This will be accomplished using mixtures of stimuli and inhibitors. The mixture experiments will indicate whether or not taste substances are binding to one or more receptors. With regard to inhibition experiments, we intend to examine the effects of some newly discovered non-stimulating sweeteners as inhibitors. Finally, in a further attempt to elucidate the number of receptor sites, experiments using single neurons will be conducted.